Home-care inhalation therapy requires a ready supply of oxygen for patient comfort. Unfortunately, available techniques for supplying oxygen all suffer from major drawbacks. The most notable common problem is excessive weight which limits patient mobility both inside and outside the home. Our objective is to demonstrate the feasibility of developing a truly portable home-care unit for inhalation therapy based upon A/G Technology Corporation's recently developed advanced hollow fiber membrane cartridges. The hollow fiber membrane geometry is exceptionally compact and can be housed in lightweight, plastic housings. This compactness, combined with the high oxygen productivity of the A/G Technology membranes may serve to free chronic obstructive pulmonary disease (COPD) outpatients from oxygen supply system portability limitations. A portable oxygen generating system will become an important innovation in COPD outpatient care for the estimated 450,000 patients currently receiving inhalation therapy at home. The commercial application of this technology will not be limited just to those patients who must have portable oxygen units, rather it is applicable to all COPD outpatients since the proposed hollow fiber membrane unit offers greater safety and convenience compared to bottled oxygen and significantly quieter operation than molecular sieve, pressure swing adsorption (PSA) oxygen "concentrators".